Checking out a repository

To check out any project repository on fd.o, run: git clone git://anongit.freedesktop.org/git/name, e.g. git://anongit.freedesktop.org/git/cairo. A full list of projects is available on cgit.

To switch to a particular branch, use git checkout branchname; a list of branches is available with git branch. If you want to use a particular tag, use git checkout -b temp tagname, e.g. git checkout -b temp xorg-server-1.1.99.3. A list of tags is available with git tag -l.

git checkout master will return to the main development branch ('trunk').

Keeping up to date

git pull will download the latest changes. Note that if you are on a branch, then you should type git pull origin branchname:branchname, otherwise you will merge the master branch, instead of simply keeping your current branch up to date.

Basic repository information

git log will give you a list of all changes. To see changes since a particular version, or between a particular version, use version1..version2 as an argument; if version1 is unspecified (i.e. ..version2), it is assumed as the first revision. Conversely, if version2 is unspecified (i.e. version1..), it is assumed as the current revision (not necessarily the most recent in the repository, but the one you currently have checked out). Examples:

git log xorg-server-1.2.0.. â changes since xorg-server 1.2.0

git log ..xorg-server-1.2.0 â changes up until xorg-server 1.2.0

git log xorg-server-1.2.0..xorg-server-1.2.1 â changes between xorg-server 1.2.0 and 1.2.1
To examine a particular revision, including the diff, run git show commitid. The commit ID does not have to be the full SHA1 sum, but only enough to be unambiguous; the first 6 characters are usually sufficient.

CVS cheat sheet

cvs checkout: git clone

cvs status: git status

cvs diff: git diff -a

cvs update: git pull (with caveats)

Bisecting

Bisecting allows you to determine which commit introduced breakage, by iterative testing. As an example, assume that the code worked one month ago, and now segfaults.

First, run git log, to determine where you want to roll back to. If it worked one month ago, say five weeks to be safe. Find the sha1 sum of the commit where you think things last worked. Take note of this (say it's 123456...).

You will get output something like: Bisecting: 297 revisions left to test after this

Run make, and check if it works. If it works, type git bisect good, else git bisect bad. This will give you a new revision to try: run make, check if it works, and type bad/good, accordingly.

If you are unable to compile a particular revision (say it's picked one that introduced a compile breakage), type git bisect god/bad, and then continue as usual. The manpage for git-bisect has some more in-depth details, as does kernel.org.